This invention relates to a telephone set, and more particularly to a loudspeaking and lowspeaking telephone set which prevents howling due to the sound coupling of a microphone and a speaker through the inner side of a transmitter-receiver casing and wherein the operation of loudspeaking and lowspeaking can be effected very easily.
In most generally used telephone sets there are many disadvantages. For example, the microphone and speaker are interconnected through the interior of the transmitter-receiver, making it easy to bring about a howling phenomenon due to the sound coupling of the two, and, further, it is not possible to switch between "lowspeaking" (one person holding the receiver of a handheld transmitter-receiver to his ear) and "loudspeaking" (a general broadcasting of sound from the receiver to the surrounding area). In order to eliminate these disadvantages, telephone sets have been developed which can effect both this loudspeaking and ordinary lowspeaking. These telephone sets are the so-called "integral type" in which a handset and a main telephone set body are integrated and the "separate type" in which the two are separated. There are, however, disadvantages with these telephone sets. In the former integral type, the set is compact, but the telephone number buttons cannot be operated during lowspeaking when the main telephone set body (including a transmitter-receiver) is handled, and the latter separate type the telephone set becomes overly large.